uniform sampler2D src;
uniform float brightness;
void main()
{
	vec4 color = texture2D(src, gl_TexCoord[0].xy);
	float cmax = min(color.b,min(color.r,color.g));
	float factor = cmax>brightness?1.0:0.0;
	color.xyz *= factor;
	gl_FragColor = color;
}